1. Field of the Invention
The invention relates to a hydrogen sensor, and hydrogen detecting system and method.
2. Description of the Related Art
H2 has been used to generate electricity in a fuel cell or a rocket propellant. Great care must be taken to store H2 because it is flammable and potentially explosive. Various H2 sensors have been proposed to detect H2 content of a gas in a storage system. A conventional H2 sensor normally includes an absorbing medium that can selectively attract or absorb H2. Several H2 absorbing mediums have been proposed in the art. One of the H2 absorbing mediums is a palladium coated substrate that has been widely used to absorb H2 for detection of the H2 content in a gas. Palladium (Pd) can react with H2 to form palladium hydride. The reaction is reversible. Since Pd and palladium hydride have different optical properties, such as reflectivity, the reflectance of a Pd coated substrate changes when H2 is adsorbed and/or absorbed on the Pd coated substrate. Hence, by measuring a change in intensity of the reflectance of the Pd coated substrate, the content of H2 can be determined. For the same H2 content, the higher the intensity change of the reflectance, the higher will be the sensitivity of the H2 sensor.